I'm having the same exact problem! We are running 5 Windows servers and 10 linux servers. After the April 5th update, all the Windows servers are running fine but all 10 of the linux servers will not start! I even tried a virgin install on a brand new linux server and I got the same error!!

Strange thing is that steamclient.dll is Windows server file! Linux uses steamclient_i486.so file and not a .dll file! So I have no freaking clue as to why Steam is ask for a .dll file on the linux servers!!

Another quailty steam update I must say... NOT!!!

I hope they release a patch soon cuz we got A LOT of angry CCS subscribers pounding on our doors right now! Maybe I should just send them over to Valve!!

The thing about the .dll files on the Linux boxes ain't a mistake. If I recall correctly, those are used to compare with the files that the gamers have on their client PC (the steamclient.dll file can be found in '..\Valve\Steam' and '..\Valve\Steam\SteamApps\<name>\counter-strike source\bin').

May the Source be with you...

Want to know which ports to forward on your router for a Source DS? Click here!

I took Zl-jm:s advice and updated glibc from 2.2.93 to 2.3.2 using the nice application Synaptic. It updated glibc and all packages that depended on that upgrade. Then I started the server, AND IT WORKS.
Forlosa is now up and running.